It actually depends on the context, but, as I feel it, the main difference between them is that when you ACCEPT something it means that you receive something with a pleasure, or at least you are satisfied with what you get :-)
When you RECEIVE something it does not necessarily means that you accept it. Well, I can say I've received your letter but I do not accept what you are saying, i.e. I am not satisfied with it.
It is the only example that comes to my mind at the moment. I'm sure other members here will have something to complement the above.
To sum up, they both have the sense of 'taking to yourself', putting it very simply:
'ACCEPT' has the sense of agreeing to something. If you are sent an estimate from a builder to do a job and you agree to the price, you would say: I accept your estimate. You can also accept someone's apology if they say they are sorry. You can accept a situation, which means you take it as it is without complaining.
'RECEIVE' has very much the idea of 'get'. You receive letters through the post/You receive payment for a piece of work. It is also used in a formal sense and usually in the passive to mean 'welcome'. He was received by the President at a formal dinner party.
Look at the following sample sentences:
Charlie received first prize in the essay writing competition.
I received this letter of apology from the bank
I think it's far too early in the morning to receive visitors
We received a complaint this morning from one of our customers.
I accept entirely what you said and understand the situation.
They accepted our gratitude and wished us every success.
I have decided to accept your invitation and will arrive this evening.
She accepted the post of manager after the interview.
Hope this help and let me know if you need any further clarification.